kernel/trace/trace_events_trigger.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * trace_events_trigger - trace event triggers
   4  *
   5  * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
   6  */
   7
   8 #include <linux/security.h>
   9 #include <linux/module.h>
  10 #include <linux/ctype.h>
  11 #include <linux/mutex.h>
  12 #include <linux/slab.h>
  13 #include <linux/rculist.h>
  14
  15 #include "trace.h"
  16
  17 static LIST_HEAD(trigger_commands);
  18 static DEFINE_MUTEX(trigger_cmd_mutex);
  19
  20 void trigger_data_free(struct event_trigger_data *data)
  21 {
  22         if (data->cmd_ops->set_filter)
  23                 data->cmd_ops->set_filter(NULL, data, NULL);
  24
  25         /* make sure current triggers exit before free */
  26         tracepoint_synchronize_unregister();
  27
  28         kfree(data);
  29 }
  30
  31 /**
  32  * event_triggers_call - Call triggers associated with a trace event
  33  * @file: The trace_event_file associated with the event
  34  * @rec: The trace entry for the event, NULL for unconditional invocation
  35  *
  36  * For each trigger associated with an event, invoke the trigger
  37  * function registered with the associated trigger command.  If rec is
  38  * non-NULL, it means that the trigger requires further processing and
  39  * shouldn't be unconditionally invoked.  If rec is non-NULL and the
  40  * trigger has a filter associated with it, rec will checked against
  41  * the filter and if the record matches the trigger will be invoked.
  42  * If the trigger is a 'post_trigger', meaning it shouldn't be invoked
  43  * in any case until the current event is written, the trigger
  44  * function isn't invoked but the bit associated with the deferred
  45  * trigger is set in the return value.
  46  *
  47  * Returns an enum event_trigger_type value containing a set bit for
  48  * any trigger that should be deferred, ETT_NONE if nothing to defer.
  49  *
  50  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
  51  *
  52  * Return: an enum event_trigger_type value containing a set bit for
  53  * any trigger that should be deferred, ETT_NONE if nothing to defer.
  54  */
  55 enum event_trigger_type
  56 event_triggers_call(struct trace_event_file *file, void *rec,
  57                     struct ring_buffer_event *event)
  58 {
  59         struct event_trigger_data *data;
  60         enum event_trigger_type tt = ETT_NONE;
  61         struct event_filter *filter;
  62
  63         if (list_empty(&file->triggers))
  64                 return tt;
  65
  66         list_for_each_entry_rcu(data, &file->triggers, list) {
  67                 if (data->paused)
  68                         continue;
  69                 if (!rec) {
  70                         data->ops->func(data, rec, event);
  71                         continue;
  72                 }
  73                 filter = rcu_dereference_sched(data->filter);
  74                 if (filter && !filter_match_preds(filter, rec))
  75                         continue;
  76                 if (event_command_post_trigger(data->cmd_ops)) {
  77                         tt |= data->cmd_ops->trigger_type;
  78                         continue;
  79                 }
  80                 data->ops->func(data, rec, event);
  81         }
  82         return tt;
  83 }
  84 EXPORT_SYMBOL_GPL(event_triggers_call);
  85
  86 /**
  87  * event_triggers_post_call - Call 'post_triggers' for a trace event
  88  * @file: The trace_event_file associated with the event
  89  * @tt: enum event_trigger_type containing a set bit for each trigger to invoke
  90  *
  91  * For each trigger associated with an event, invoke the trigger
  92  * function registered with the associated trigger command, if the
  93  * corresponding bit is set in the tt enum passed into this function.
  94  * See @event_triggers_call for details on how those bits are set.
  95  *
  96  * Called from tracepoint handlers (with rcu_read_lock_sched() held).
  97  */
  98 void
  99 event_triggers_post_call(struct trace_event_file *file,
 100                          enum event_trigger_type tt)
 101 {
 102         struct event_trigger_data *data;
 103
 104         list_for_each_entry_rcu(data, &file->triggers, list) {
 105                 if (data->paused)
 106                         continue;
 107                 if (data->cmd_ops->trigger_type & tt)
 108                         data->ops->func(data, NULL, NULL);
 109         }
 110 }
 111 EXPORT_SYMBOL_GPL(event_triggers_post_call);
 112
 113 #define SHOW_AVAILABLE_TRIGGERS (void *)(1UL)
 114
 115 static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
 116 {
 117         struct trace_event_file *event_file = event_file_data(m->private);
 118
 119         if (t == SHOW_AVAILABLE_TRIGGERS) {
 120                 (*pos)++;
 121                 return NULL;
 122         }
 123         return seq_list_next(t, &event_file->triggers, pos);
 124 }
 125
 126 static void *trigger_start(struct seq_file *m, loff_t *pos)
 127 {
 128         struct trace_event_file *event_file;
 129
 130         /* ->stop() is called even if ->start() fails */
 131         mutex_lock(&event_mutex);
 132         event_file = event_file_data(m->private);
 133         if (unlikely(!event_file))
 134                 return ERR_PTR(-ENODEV);
 135
 136         if (list_empty(&event_file->triggers))
 137                 return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL;
 138
 139         return seq_list_start(&event_file->triggers, *pos);
 140 }
 141
 142 static void trigger_stop(struct seq_file *m, void *t)
 143 {
 144         mutex_unlock(&event_mutex);
 145 }
 146
 147 static int trigger_show(struct seq_file *m, void *v)
 148 {
 149         struct event_trigger_data *data;
 150         struct event_command *p;
 151
 152         if (v == SHOW_AVAILABLE_TRIGGERS) {
 153                 seq_puts(m, "# Available triggers:\n");
 154                 seq_putc(m, '#');
 155                 mutex_lock(&trigger_cmd_mutex);
 156                 list_for_each_entry_reverse(p, &trigger_commands, list)
 157                         seq_printf(m, " %s", p->name);
 158                 seq_putc(m, '\n');
 159                 mutex_unlock(&trigger_cmd_mutex);
 160                 return 0;
 161         }
 162
 163         data = list_entry(v, struct event_trigger_data, list);
 164         data->ops->print(m, data->ops, data);
 165
 166         return 0;
 167 }
 168
 169 static const struct seq_operations event_triggers_seq_ops = {
 170         .start = trigger_start,
 171         .next = trigger_next,
 172         .stop = trigger_stop,
 173         .show = trigger_show,
 174 };
 175
 176 static int event_trigger_regex_open(struct inode *inode, struct file *file)
 177 {
 178         int ret;
 179
 180         ret = security_locked_down(LOCKDOWN_TRACEFS);
 181         if (ret)
 182                 return ret;
 183
 184         mutex_lock(&event_mutex);
 185
 186         if (unlikely(!event_file_data(file))) {
 187                 mutex_unlock(&event_mutex);
 188                 return -ENODEV;
 189         }
 190
 191         if ((file->f_mode & FMODE_WRITE) &&
 192             (file->f_flags & O_TRUNC)) {
 193                 struct trace_event_file *event_file;
 194                 struct event_command *p;
 195
 196                 event_file = event_file_data(file);
 197
 198                 list_for_each_entry(p, &trigger_commands, list) {
 199                         if (p->unreg_all)
 200                                 p->unreg_all(event_file);
 201                 }
 202         }
 203
 204         if (file->f_mode & FMODE_READ) {
 205                 ret = seq_open(file, &event_triggers_seq_ops);
 206                 if (!ret) {
 207                         struct seq_file *m = file->private_data;
 208                         m->private = file;
 209                 }
 210         }
 211
 212         mutex_unlock(&event_mutex);
 213
 214         return ret;
 215 }
 216
 217 int trigger_process_regex(struct trace_event_file *file, char *buff)
 218 {
 219         char *command, *next = buff;
 220         struct event_command *p;
 221         int ret = -EINVAL;
 222
 223         command = strsep(&next, ": \t");
 224         command = (command[0] != '!') ? command : command + 1;
 225
 226         mutex_lock(&trigger_cmd_mutex);
 227         list_for_each_entry(p, &trigger_commands, list) {
 228                 if (strcmp(p->name, command) == 0) {
 229                         ret = p->func(p, file, buff, command, next);
 230                         goto out_unlock;
 231                 }
 232         }
 233  out_unlock:
 234         mutex_unlock(&trigger_cmd_mutex);
 235
 236         return ret;
 237 }
 238
 239 static ssize_t event_trigger_regex_write(struct file *file,
 240                                          const char __user *ubuf,
 241                                          size_t cnt, loff_t *ppos)
 242 {
 243         struct trace_event_file *event_file;
 244         ssize_t ret;
 245         char *buf;
 246
 247         if (!cnt)
 248                 return 0;
 249
 250         if (cnt >= PAGE_SIZE)
 251                 return -EINVAL;
 252
 253         buf = memdup_user_nul(ubuf, cnt);
 254         if (IS_ERR(buf))
 255                 return PTR_ERR(buf);
 256
 257         strim(buf);
 258
 259         mutex_lock(&event_mutex);
 260         event_file = event_file_data(file);
 261         if (unlikely(!event_file)) {
 262                 mutex_unlock(&event_mutex);
 263                 kfree(buf);
 264                 return -ENODEV;
 265         }
 266         ret = trigger_process_regex(event_file, buf);
 267         mutex_unlock(&event_mutex);
 268
 269         kfree(buf);
 270         if (ret < 0)
 271                 goto out;
 272
 273         *ppos += cnt;
 274         ret = cnt;
 275  out:
 276         return ret;
 277 }
 278
 279 static int event_trigger_regex_release(struct inode *inode, struct file *file)
 280 {
 281         mutex_lock(&event_mutex);
 282
 283         if (file->f_mode & FMODE_READ)
 284                 seq_release(inode, file);
 285
 286         mutex_unlock(&event_mutex);
 287
 288         return 0;
 289 }
 290
 291 static ssize_t
 292 event_trigger_write(struct file *filp, const char __user *ubuf,
 293                     size_t cnt, loff_t *ppos)
 294 {
 295         return event_trigger_regex_write(filp, ubuf, cnt, ppos);
 296 }
 297
 298 static int
 299 event_trigger_open(struct inode *inode, struct file *filp)
 300 {
 301         /* Checks for tracefs lockdown */
 302         return event_trigger_regex_open(inode, filp);
 303 }
 304
 305 static int
 306 event_trigger_release(struct inode *inode, struct file *file)
 307 {
 308         return event_trigger_regex_release(inode, file);
 309 }
 310
 311 const struct file_operations event_trigger_fops = {
 312         .open = event_trigger_open,
 313         .read = seq_read,
 314         .write = event_trigger_write,
 315         .llseek = tracing_lseek,
 316         .release = event_trigger_release,
 317 };
 318
 319 /*
 320  * Currently we only register event commands from __init, so mark this
 321  * __init too.
 322  */
 323 __init int register_event_command(struct event_command *cmd)
 324 {
 325         struct event_command *p;
 326         int ret = 0;
 327
 328         mutex_lock(&trigger_cmd_mutex);
 329         list_for_each_entry(p, &trigger_commands, list) {
 330                 if (strcmp(cmd->name, p->name) == 0) {
 331                         ret = -EBUSY;
 332                         goto out_unlock;
 333                 }
 334         }
 335         list_add(&cmd->list, &trigger_commands);
 336  out_unlock:
 337         mutex_unlock(&trigger_cmd_mutex);
 338
 339         return ret;
 340 }
 341
 342 /*
 343  * Currently we only unregister event commands from __init, so mark
 344  * this __init too.
 345  */
 346 __init int unregister_event_command(struct event_command *cmd)
 347 {
 348         struct event_command *p, *n;
 349         int ret = -ENODEV;
 350
 351         mutex_lock(&trigger_cmd_mutex);
 352         list_for_each_entry_safe(p, n, &trigger_commands, list) {
 353                 if (strcmp(cmd->name, p->name) == 0) {
 354                         ret = 0;
 355                         list_del_init(&p->list);
 356                         goto out_unlock;
 357                 }
 358         }
 359  out_unlock:
 360         mutex_unlock(&trigger_cmd_mutex);
 361
 362         return ret;
 363 }
 364
 365 /**
 366  * event_trigger_print - Generic event_trigger_ops @print implementation
 367  * @name: The name of the event trigger
 368  * @m: The seq_file being printed to
 369  * @data: Trigger-specific data
 370  * @filter_str: filter_str to print, if present
 371  *
 372  * Common implementation for event triggers to print themselves.
 373  *
 374  * Usually wrapped by a function that simply sets the @name of the
 375  * trigger command and then invokes this.
 376  *
 377  * Return: 0 on success, errno otherwise
 378  */
 379 static int
 380 event_trigger_print(const char *name, struct seq_file *m,
 381                     void *data, char *filter_str)
 382 {
 383         long count = (long)data;
 384
 385         seq_puts(m, name);
 386
 387         if (count == -1)
 388                 seq_puts(m, ":unlimited");
 389         else
 390                 seq_printf(m, ":count=%ld", count);
 391
 392         if (filter_str)
 393                 seq_printf(m, " if %s\n", filter_str);
 394         else
 395                 seq_putc(m, '\n');
 396
 397         return 0;
 398 }
 399
 400 /**
 401  * event_trigger_init - Generic event_trigger_ops @init implementation
 402  * @ops: The trigger ops associated with the trigger
 403  * @data: Trigger-specific data
 404  *
 405  * Common implementation of event trigger initialization.
 406  *
 407  * Usually used directly as the @init method in event trigger
 408  * implementations.
 409  *
 410  * Return: 0 on success, errno otherwise
 411  */
 412 int event_trigger_init(struct event_trigger_ops *ops,
 413                        struct event_trigger_data *data)
 414 {
 415         data->ref++;
 416         return 0;
 417 }
 418
 419 /**
 420  * event_trigger_free - Generic event_trigger_ops @free implementation
 421  * @ops: The trigger ops associated with the trigger
 422  * @data: Trigger-specific data
 423  *
 424  * Common implementation of event trigger de-initialization.
 425  *
 426  * Usually used directly as the @free method in event trigger
 427  * implementations.
 428  */
 429 static void
 430 event_trigger_free(struct event_trigger_ops *ops,
 431                    struct event_trigger_data *data)
 432 {
 433         if (WARN_ON_ONCE(data->ref <= 0))
 434                 return;
 435
 436         data->ref--;
 437         if (!data->ref)
 438                 trigger_data_free(data);
 439 }
 440
 441 int trace_event_trigger_enable_disable(struct trace_event_file *file,
 442                                        int trigger_enable)
 443 {
 444         int ret = 0;
 445
 446         if (trigger_enable) {
 447                 if (atomic_inc_return(&file->tm_ref) > 1)
 448                         return ret;
 449                 set_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 450                 ret = trace_event_enable_disable(file, 1, 1);
 451         } else {
 452                 if (atomic_dec_return(&file->tm_ref) > 0)
 453                         return ret;
 454                 clear_bit(EVENT_FILE_FL_TRIGGER_MODE_BIT, &file->flags);
 455                 ret = trace_event_enable_disable(file, 0, 1);
 456         }
 457
 458         return ret;
 459 }
 460
 461 /**
 462  * clear_event_triggers - Clear all triggers associated with a trace array
 463  * @tr: The trace array to clear
 464  *
 465  * For each trigger, the triggering event has its tm_ref decremented
 466  * via trace_event_trigger_enable_disable(), and any associated event
 467  * (in the case of enable/disable_event triggers) will have its sm_ref
 468  * decremented via free()->trace_event_enable_disable().  That
 469  * combination effectively reverses the soft-mode/trigger state added
 470  * by trigger registration.
 471  *
 472  * Must be called with event_mutex held.
 473  */
 474 void
 475 clear_event_triggers(struct trace_array *tr)
 476 {
 477         struct trace_event_file *file;
 478
 479         list_for_each_entry(file, &tr->events, list) {
 480                 struct event_trigger_data *data, *n;
 481                 list_for_each_entry_safe(data, n, &file->triggers, list) {
 482                         trace_event_trigger_enable_disable(file, 0);
 483                         list_del_rcu(&data->list);
 484                         if (data->ops->free)
 485                                 data->ops->free(data->ops, data);
 486                 }
 487         }
 488 }
 489
 490 /**
 491  * update_cond_flag - Set or reset the TRIGGER_COND bit
 492  * @file: The trace_event_file associated with the event
 493  *
 494  * If an event has triggers and any of those triggers has a filter or
 495  * a post_trigger, trigger invocation needs to be deferred until after
 496  * the current event has logged its data, and the event should have
 497  * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be
 498  * cleared.
 499  */
 500 void update_cond_flag(struct trace_event_file *file)
 501 {
 502         struct event_trigger_data *data;
 503         bool set_cond = false;
 504
 505         lockdep_assert_held(&event_mutex);
 506
 507         list_for_each_entry(data, &file->triggers, list) {
 508                 if (data->filter || event_command_post_trigger(data->cmd_ops) ||
 509                     event_command_needs_rec(data->cmd_ops)) {
 510                         set_cond = true;
 511                         break;
 512                 }
 513         }
 514
 515         if (set_cond)
 516                 set_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 517         else
 518                 clear_bit(EVENT_FILE_FL_TRIGGER_COND_BIT, &file->flags);
 519 }
 520
 521 /**
 522  * register_trigger - Generic event_command @reg implementation
 523  * @glob: The raw string used to register the trigger
 524  * @ops: The trigger ops associated with the trigger
 525  * @data: Trigger-specific data to associate with the trigger
 526  * @file: The trace_event_file associated with the event
 527  *
 528  * Common implementation for event trigger registration.
 529  *
 530  * Usually used directly as the @reg method in event command
 531  * implementations.
 532  *
 533  * Return: 0 on success, errno otherwise
 534  */
 535 static int register_trigger(char *glob, struct event_trigger_ops *ops,
 536                             struct event_trigger_data *data,
 537                             struct trace_event_file *file)
 538 {
 539         struct event_trigger_data *test;
 540         int ret = 0;
 541
 542         lockdep_assert_held(&event_mutex);
 543
 544         list_for_each_entry(test, &file->triggers, list) {
 545                 if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) {
 546                         ret = -EEXIST;
 547                         goto out;
 548                 }
 549         }
 550
 551         if (data->ops->init) {
 552                 ret = data->ops->init(data->ops, data);
 553                 if (ret < 0)
 554                         goto out;
 555         }
 556
 557         list_add_rcu(&data->list, &file->triggers);
 558         ret++;
 559
 560         update_cond_flag(file);
 561         if (trace_event_trigger_enable_disable(file, 1) < 0) {
 562                 list_del_rcu(&data->list);
 563                 update_cond_flag(file);
 564                 ret--;
 565         }
 566 out:
 567         return ret;
 568 }
 569
 570 /**
 571  * unregister_trigger - Generic event_command @unreg implementation
 572  * @glob: The raw string used to register the trigger
 573  * @ops: The trigger ops associated with the trigger
 574  * @test: Trigger-specific data used to find the trigger to remove
 575  * @file: The trace_event_file associated with the event
 576  *
 577  * Common implementation for event trigger unregistration.
 578  *
 579  * Usually used directly as the @unreg method in event command
 580  * implementations.
 581  */
 582 static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
 583                                struct event_trigger_data *test,
 584                                struct trace_event_file *file)
 585 {
 586         struct event_trigger_data *data;
 587         bool unregistered = false;
 588
 589         lockdep_assert_held(&event_mutex);
 590
 591         list_for_each_entry(data, &file->triggers, list) {
 592                 if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) {
 593                         unregistered = true;
 594                         list_del_rcu(&data->list);
 595                         trace_event_trigger_enable_disable(file, 0);
 596                         update_cond_flag(file);
 597                         break;
 598                 }
 599         }
 600
 601         if (unregistered && data->ops->free)
 602                 data->ops->free(data->ops, data);
 603 }
 604
 605 /**
 606  * event_trigger_callback - Generic event_command @func implementation
 607  * @cmd_ops: The command ops, used for trigger registration
 608  * @file: The trace_event_file associated with the event
 609  * @glob: The raw string used to register the trigger
 610  * @cmd: The cmd portion of the string used to register the trigger
 611  * @param: The params portion of the string used to register the trigger
 612  *
 613  * Common implementation for event command parsing and trigger
 614  * instantiation.
 615  *
 616  * Usually used directly as the @func method in event command
 617  * implementations.
 618  *
 619  * Return: 0 on success, errno otherwise
 620  */
 621 static int
 622 event_trigger_callback(struct event_command *cmd_ops,
 623                        struct trace_event_file *file,
 624                        char *glob, char *cmd, char *param)
 625 {
 626         struct event_trigger_data *trigger_data;
 627         struct event_trigger_ops *trigger_ops;
 628         char *trigger = NULL;
 629         char *number;
 630         int ret;
 631
 632         /* separate the trigger from the filter (t:n [if filter]) */
 633         if (param && isdigit(param[0]))
 634                 trigger = strsep(&param, " \t");
 635
 636         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
 637
 638         ret = -ENOMEM;
 639         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
 640         if (!trigger_data)
 641                 goto out;
 642
 643         trigger_data->count = -1;
 644         trigger_data->ops = trigger_ops;
 645         trigger_data->cmd_ops = cmd_ops;
 646         trigger_data->private_data = file;
 647         INIT_LIST_HEAD(&trigger_data->list);
 648         INIT_LIST_HEAD(&trigger_data->named_list);
 649
 650         if (glob[0] == '!') {
 651                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
 652                 kfree(trigger_data);
 653                 ret = 0;
 654                 goto out;
 655         }
 656
 657         if (trigger) {
 658                 number = strsep(&trigger, ":");
 659
 660                 ret = -EINVAL;
 661                 if (!strlen(number))
 662                         goto out_free;
 663
 664                 /*
 665                  * We use the callback data field (which is a pointer)
 666                  * as our counter.
 667                  */
 668                 ret = kstrtoul(number, 0, &trigger_data->count);
 669                 if (ret)
 670                         goto out_free;
 671         }
 672
 673         if (!param) /* if param is non-empty, it's supposed to be a filter */
 674                 goto out_reg;
 675
 676         if (!cmd_ops->set_filter)
 677                 goto out_reg;
 678
 679         ret = cmd_ops->set_filter(param, trigger_data, file);
 680         if (ret < 0)
 681                 goto out_free;
 682
 683  out_reg:
 684         /* Up the trigger_data count to make sure reg doesn't free it on failure */
 685         event_trigger_init(trigger_ops, trigger_data);
 686         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
 687         /*
 688          * The above returns on success the # of functions enabled,
 689          * but if it didn't find any functions it returns zero.
 690          * Consider no functions a failure too.
 691          */
 692         if (!ret) {
 693                 cmd_ops->unreg(glob, trigger_ops, trigger_data, file);
 694                 ret = -ENOENT;
 695         } else if (ret > 0)
 696                 ret = 0;
 697
 698         /* Down the counter of trigger_data or free it if not used anymore */
 699         event_trigger_free(trigger_ops, trigger_data);
 700  out:
 701         return ret;
 702
 703  out_free:
 704         if (cmd_ops->set_filter)
 705                 cmd_ops->set_filter(NULL, trigger_data, NULL);
 706         kfree(trigger_data);
 707         goto out;
 708 }
 709
 710 /**
 711  * set_trigger_filter - Generic event_command @set_filter implementation
 712  * @filter_str: The filter string for the trigger, NULL to remove filter
 713  * @trigger_data: Trigger-specific data
 714  * @file: The trace_event_file associated with the event
 715  *
 716  * Common implementation for event command filter parsing and filter
 717  * instantiation.
 718  *
 719  * Usually used directly as the @set_filter method in event command
 720  * implementations.
 721  *
 722  * Also used to remove a filter (if filter_str = NULL).
 723  *
 724  * Return: 0 on success, errno otherwise
 725  */
 726 int set_trigger_filter(char *filter_str,
 727                        struct event_trigger_data *trigger_data,
 728                        struct trace_event_file *file)
 729 {
 730         struct event_trigger_data *data = trigger_data;
 731         struct event_filter *filter = NULL, *tmp;
 732         int ret = -EINVAL;
 733         char *s;
 734
 735         if (!filter_str) /* clear the current filter */
 736                 goto assign;
 737
 738         s = strsep(&filter_str, " \t");
 739
 740         if (!strlen(s) || strcmp(s, "if") != 0)
 741                 goto out;
 742
 743         if (!filter_str)
 744                 goto out;
 745
 746         /* The filter is for the 'trigger' event, not the triggered event */
 747         ret = create_event_filter(file->tr, file->event_call,
 748                                   filter_str, false, &filter);
 749         /*
 750          * If create_event_filter() fails, filter still needs to be freed.
 751          * Which the calling code will do with data->filter.
 752          */
 753  assign:
 754         tmp = rcu_access_pointer(data->filter);
 755
 756         rcu_assign_pointer(data->filter, filter);
 757
 758         if (tmp) {
 759                 /* Make sure the call is done with the filter */
 760                 tracepoint_synchronize_unregister();
 761                 free_event_filter(tmp);
 762         }
 763
 764         kfree(data->filter_str);
 765         data->filter_str = NULL;
 766
 767         if (filter_str) {
 768                 data->filter_str = kstrdup(filter_str, GFP_KERNEL);
 769                 if (!data->filter_str) {
 770                         free_event_filter(rcu_access_pointer(data->filter));
 771                         data->filter = NULL;
 772                         ret = -ENOMEM;
 773                 }
 774         }
 775  out:
 776         return ret;
 777 }
 778
 779 static LIST_HEAD(named_triggers);
 780
 781 /**
 782  * find_named_trigger - Find the common named trigger associated with @name
 783  * @name: The name of the set of named triggers to find the common data for
 784  *
 785  * Named triggers are sets of triggers that share a common set of
 786  * trigger data.  The first named trigger registered with a given name
 787  * owns the common trigger data that the others subsequently
 788  * registered with the same name will reference.  This function
 789  * returns the common trigger data associated with that first
 790  * registered instance.
 791  *
 792  * Return: the common trigger data for the given named trigger on
 793  * success, NULL otherwise.
 794  */
 795 struct event_trigger_data *find_named_trigger(const char *name)
 796 {
 797         struct event_trigger_data *data;
 798
 799         if (!name)
 800                 return NULL;
 801
 802         list_for_each_entry(data, &named_triggers, named_list) {
 803                 if (data->named_data)
 804                         continue;
 805                 if (strcmp(data->name, name) == 0)
 806                         return data;
 807         }
 808
 809         return NULL;
 810 }
 811
 812 /**
 813  * is_named_trigger - determine if a given trigger is a named trigger
 814  * @test: The trigger data to test
 815  *
 816  * Return: true if 'test' is a named trigger, false otherwise.
 817  */
 818 bool is_named_trigger(struct event_trigger_data *test)
 819 {
 820         struct event_trigger_data *data;
 821
 822         list_for_each_entry(data, &named_triggers, named_list) {
 823                 if (test == data)
 824                         return true;
 825         }
 826
 827         return false;
 828 }
 829
 830 /**
 831  * save_named_trigger - save the trigger in the named trigger list
 832  * @name: The name of the named trigger set
 833  * @data: The trigger data to save
 834  *
 835  * Return: 0 if successful, negative error otherwise.
 836  */
 837 int save_named_trigger(const char *name, struct event_trigger_data *data)
 838 {
 839         data->name = kstrdup(name, GFP_KERNEL);
 840         if (!data->name)
 841                 return -ENOMEM;
 842
 843         list_add(&data->named_list, &named_triggers);
 844
 845         return 0;
 846 }
 847
 848 /**
 849  * del_named_trigger - delete a trigger from the named trigger list
 850  * @data: The trigger data to delete
 851  */
 852 void del_named_trigger(struct event_trigger_data *data)
 853 {
 854         kfree(data->name);
 855         data->name = NULL;
 856
 857         list_del(&data->named_list);
 858 }
 859
 860 static void __pause_named_trigger(struct event_trigger_data *data, bool pause)
 861 {
 862         struct event_trigger_data *test;
 863
 864         list_for_each_entry(test, &named_triggers, named_list) {
 865                 if (strcmp(test->name, data->name) == 0) {
 866                         if (pause) {
 867                                 test->paused_tmp = test->paused;
 868                                 test->paused = true;
 869                         } else {
 870                                 test->paused = test->paused_tmp;
 871                         }
 872                 }
 873         }
 874 }
 875
 876 /**
 877  * pause_named_trigger - Pause all named triggers with the same name
 878  * @data: The trigger data of a named trigger to pause
 879  *
 880  * Pauses a named trigger along with all other triggers having the
 881  * same name.  Because named triggers share a common set of data,
 882  * pausing only one is meaningless, so pausing one named trigger needs
 883  * to pause all triggers with the same name.
 884  */
 885 void pause_named_trigger(struct event_trigger_data *data)
 886 {
 887         __pause_named_trigger(data, true);
 888 }
 889
 890 /**
 891  * unpause_named_trigger - Un-pause all named triggers with the same name
 892  * @data: The trigger data of a named trigger to unpause
 893  *
 894  * Un-pauses a named trigger along with all other triggers having the
 895  * same name.  Because named triggers share a common set of data,
 896  * unpausing only one is meaningless, so unpausing one named trigger
 897  * needs to unpause all triggers with the same name.
 898  */
 899 void unpause_named_trigger(struct event_trigger_data *data)
 900 {
 901         __pause_named_trigger(data, false);
 902 }
 903
 904 /**
 905  * set_named_trigger_data - Associate common named trigger data
 906  * @data: The trigger data of a named trigger to unpause
 907  *
 908  * Named triggers are sets of triggers that share a common set of
 909  * trigger data.  The first named trigger registered with a given name
 910  * owns the common trigger data that the others subsequently
 911  * registered with the same name will reference.  This function
 912  * associates the common trigger data from the first trigger with the
 913  * given trigger.
 914  */
 915 void set_named_trigger_data(struct event_trigger_data *data,
 916                             struct event_trigger_data *named_data)
 917 {
 918         data->named_data = named_data;
 919 }
 920
 921 struct event_trigger_data *
 922 get_named_trigger_data(struct event_trigger_data *data)
 923 {
 924         return data->named_data;
 925 }
 926
 927 static void
 928 traceon_trigger(struct event_trigger_data *data, void *rec,
 929                 struct ring_buffer_event *event)
 930 {
 931         if (tracing_is_on())
 932                 return;
 933
 934         tracing_on();
 935 }
 936
 937 static void
 938 traceon_count_trigger(struct event_trigger_data *data, void *rec,
 939                       struct ring_buffer_event *event)
 940 {
 941         if (tracing_is_on())
 942                 return;
 943
 944         if (!data->count)
 945                 return;
 946
 947         if (data->count != -1)
 948                 (data->count)--;
 949
 950         tracing_on();
 951 }
 952
 953 static void
 954 traceoff_trigger(struct event_trigger_data *data, void *rec,
 955                  struct ring_buffer_event *event)
 956 {
 957         if (!tracing_is_on())
 958                 return;
 959
 960         tracing_off();
 961 }
 962
 963 static void
 964 traceoff_count_trigger(struct event_trigger_data *data, void *rec,
 965                        struct ring_buffer_event *event)
 966 {
 967         if (!tracing_is_on())
 968                 return;
 969
 970         if (!data->count)
 971                 return;
 972
 973         if (data->count != -1)
 974                 (data->count)--;
 975
 976         tracing_off();
 977 }
 978
 979 static int
 980 traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 981                       struct event_trigger_data *data)
 982 {
 983         return event_trigger_print("traceon", m, (void *)data->count,
 984                                    data->filter_str);
 985 }
 986
 987 static int
 988 traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
 989                        struct event_trigger_data *data)
 990 {
 991         return event_trigger_print("traceoff", m, (void *)data->count,
 992                                    data->filter_str);
 993 }
 994
 995 static struct event_trigger_ops traceon_trigger_ops = {
 996         .func                   = traceon_trigger,
 997         .print                  = traceon_trigger_print,
 998         .init                   = event_trigger_init,
 999         .free                   = event_trigger_free,
1000 };
1001
1002 static struct event_trigger_ops traceon_count_trigger_ops = {
1003         .func                   = traceon_count_trigger,
1004         .print                  = traceon_trigger_print,
1005         .init                   = event_trigger_init,
1006         .free                   = event_trigger_free,
1007 };
1008
1009 static struct event_trigger_ops traceoff_trigger_ops = {
1010         .func                   = traceoff_trigger,
1011         .print                  = traceoff_trigger_print,
1012         .init                   = event_trigger_init,
1013         .free                   = event_trigger_free,
1014 };
1015
1016 static struct event_trigger_ops traceoff_count_trigger_ops = {
1017         .func                   = traceoff_count_trigger,
1018         .print                  = traceoff_trigger_print,
1019         .init                   = event_trigger_init,
1020         .free                   = event_trigger_free,
1021 };
1022
1023 static struct event_trigger_ops *
1024 onoff_get_trigger_ops(char *cmd, char *param)
1025 {
1026         struct event_trigger_ops *ops;
1027
1028         /* we register both traceon and traceoff to this callback */
1029         if (strcmp(cmd, "traceon") == 0)
1030                 ops = param ? &traceon_count_trigger_ops :
1031                         &traceon_trigger_ops;
1032         else
1033                 ops = param ? &traceoff_count_trigger_ops :
1034                         &traceoff_trigger_ops;
1035
1036         return ops;
1037 }
1038
1039 static struct event_command trigger_traceon_cmd = {
1040         .name                   = "traceon",
1041         .trigger_type           = ETT_TRACE_ONOFF,
1042         .func                   = event_trigger_callback,
1043         .reg                    = register_trigger,
1044         .unreg                  = unregister_trigger,
1045         .get_trigger_ops        = onoff_get_trigger_ops,
1046         .set_filter             = set_trigger_filter,
1047 };
1048
1049 static struct event_command trigger_traceoff_cmd = {
1050         .name                   = "traceoff",
1051         .trigger_type           = ETT_TRACE_ONOFF,
1052         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1053         .func                   = event_trigger_callback,
1054         .reg                    = register_trigger,
1055         .unreg                  = unregister_trigger,
1056         .get_trigger_ops        = onoff_get_trigger_ops,
1057         .set_filter             = set_trigger_filter,
1058 };
1059
1060 #ifdef CONFIG_TRACER_SNAPSHOT
1061 static void
1062 snapshot_trigger(struct event_trigger_data *data, void *rec,
1063                  struct ring_buffer_event *event)
1064 {
1065         struct trace_event_file *file = data->private_data;
1066
1067         if (file)
1068                 tracing_snapshot_instance(file->tr);
1069         else
1070                 tracing_snapshot();
1071 }
1072
1073 static void
1074 snapshot_count_trigger(struct event_trigger_data *data, void *rec,
1075                        struct ring_buffer_event *event)
1076 {
1077         if (!data->count)
1078                 return;
1079
1080         if (data->count != -1)
1081                 (data->count)--;
1082
1083         snapshot_trigger(data, rec, event);
1084 }
1085
1086 static int
1087 register_snapshot_trigger(char *glob, struct event_trigger_ops *ops,
1088                           struct event_trigger_data *data,
1089                           struct trace_event_file *file)
1090 {
1091         if (tracing_alloc_snapshot_instance(file->tr) != 0)
1092                 return 0;
1093
1094         return register_trigger(glob, ops, data, file);
1095 }
1096
1097 static int
1098 snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1099                        struct event_trigger_data *data)
1100 {
1101         return event_trigger_print("snapshot", m, (void *)data->count,
1102                                    data->filter_str);
1103 }
1104
1105 static struct event_trigger_ops snapshot_trigger_ops = {
1106         .func                   = snapshot_trigger,
1107         .print                  = snapshot_trigger_print,
1108         .init                   = event_trigger_init,
1109         .free                   = event_trigger_free,
1110 };
1111
1112 static struct event_trigger_ops snapshot_count_trigger_ops = {
1113         .func                   = snapshot_count_trigger,
1114         .print                  = snapshot_trigger_print,
1115         .init                   = event_trigger_init,
1116         .free                   = event_trigger_free,
1117 };
1118
1119 static struct event_trigger_ops *
1120 snapshot_get_trigger_ops(char *cmd, char *param)
1121 {
1122         return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops;
1123 }
1124
1125 static struct event_command trigger_snapshot_cmd = {
1126         .name                   = "snapshot",
1127         .trigger_type           = ETT_SNAPSHOT,
1128         .func                   = event_trigger_callback,
1129         .reg                    = register_snapshot_trigger,
1130         .unreg                  = unregister_trigger,
1131         .get_trigger_ops        = snapshot_get_trigger_ops,
1132         .set_filter             = set_trigger_filter,
1133 };
1134
1135 static __init int register_trigger_snapshot_cmd(void)
1136 {
1137         int ret;
1138
1139         ret = register_event_command(&trigger_snapshot_cmd);
1140         WARN_ON(ret < 0);
1141
1142         return ret;
1143 }
1144 #else
1145 static __init int register_trigger_snapshot_cmd(void) { return 0; }
1146 #endif /* CONFIG_TRACER_SNAPSHOT */
1147
1148 #ifdef CONFIG_STACKTRACE
1149 #ifdef CONFIG_UNWINDER_ORC
1150 /* Skip 2:
1151  *   event_triggers_post_call()
1152  *   trace_event_raw_event_xxx()
1153  */
1154 # define STACK_SKIP 2
1155 #else
1156 /*
1157  * Skip 4:
1158  *   stacktrace_trigger()
1159  *   event_triggers_post_call()
1160  *   trace_event_buffer_commit()
1161  *   trace_event_raw_event_xxx()
1162  */
1163 #define STACK_SKIP 4
1164 #endif
1165
1166 static void
1167 stacktrace_trigger(struct event_trigger_data *data, void *rec,
1168                    struct ring_buffer_event *event)
1169 {
1170         trace_dump_stack(STACK_SKIP);
1171 }
1172
1173 static void
1174 stacktrace_count_trigger(struct event_trigger_data *data, void *rec,
1175                          struct ring_buffer_event *event)
1176 {
1177         if (!data->count)
1178                 return;
1179
1180         if (data->count != -1)
1181                 (data->count)--;
1182
1183         stacktrace_trigger(data, rec, event);
1184 }
1185
1186 static int
1187 stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops,
1188                          struct event_trigger_data *data)
1189 {
1190         return event_trigger_print("stacktrace", m, (void *)data->count,
1191                                    data->filter_str);
1192 }
1193
1194 static struct event_trigger_ops stacktrace_trigger_ops = {
1195         .func                   = stacktrace_trigger,
1196         .print                  = stacktrace_trigger_print,
1197         .init                   = event_trigger_init,
1198         .free                   = event_trigger_free,
1199 };
1200
1201 static struct event_trigger_ops stacktrace_count_trigger_ops = {
1202         .func                   = stacktrace_count_trigger,
1203         .print                  = stacktrace_trigger_print,
1204         .init                   = event_trigger_init,
1205         .free                   = event_trigger_free,
1206 };
1207
1208 static struct event_trigger_ops *
1209 stacktrace_get_trigger_ops(char *cmd, char *param)
1210 {
1211         return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops;
1212 }
1213
1214 static struct event_command trigger_stacktrace_cmd = {
1215         .name                   = "stacktrace",
1216         .trigger_type           = ETT_STACKTRACE,
1217         .flags                  = EVENT_CMD_FL_POST_TRIGGER,
1218         .func                   = event_trigger_callback,
1219         .reg                    = register_trigger,
1220         .unreg                  = unregister_trigger,
1221         .get_trigger_ops        = stacktrace_get_trigger_ops,
1222         .set_filter             = set_trigger_filter,
1223 };
1224
1225 static __init int register_trigger_stacktrace_cmd(void)
1226 {
1227         int ret;
1228
1229         ret = register_event_command(&trigger_stacktrace_cmd);
1230         WARN_ON(ret < 0);
1231
1232         return ret;
1233 }
1234 #else
1235 static __init int register_trigger_stacktrace_cmd(void) { return 0; }
1236 #endif /* CONFIG_STACKTRACE */
1237
1238 static __init void unregister_trigger_traceon_traceoff_cmds(void)
1239 {
1240         unregister_event_command(&trigger_traceon_cmd);
1241         unregister_event_command(&trigger_traceoff_cmd);
1242 }
1243
1244 static void
1245 event_enable_trigger(struct event_trigger_data *data, void *rec,
1246                      struct ring_buffer_event *event)
1247 {
1248         struct enable_trigger_data *enable_data = data->private_data;
1249
1250         if (enable_data->enable)
1251                 clear_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1252         else
1253                 set_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &enable_data->file->flags);
1254 }
1255
1256 static void
1257 event_enable_count_trigger(struct event_trigger_data *data, void *rec,
1258                            struct ring_buffer_event *event)
1259 {
1260         struct enable_trigger_data *enable_data = data->private_data;
1261
1262         if (!data->count)
1263                 return;
1264
1265         /* Skip if the event is in a state we want to switch to */
1266         if (enable_data->enable == !(enable_data->file->flags & EVENT_FILE_FL_SOFT_DISABLED))
1267                 return;
1268
1269         if (data->count != -1)
1270                 (data->count)--;
1271
1272         event_enable_trigger(data, rec, event);
1273 }
1274
1275 int event_enable_trigger_print(struct seq_file *m,
1276                                struct event_trigger_ops *ops,
1277                                struct event_trigger_data *data)
1278 {
1279         struct enable_trigger_data *enable_data = data->private_data;
1280
1281         seq_printf(m, "%s:%s:%s",
1282                    enable_data->hist ?
1283                    (enable_data->enable ? ENABLE_HIST_STR : DISABLE_HIST_STR) :
1284                    (enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR),
1285                    enable_data->file->event_call->class->system,
1286                    trace_event_name(enable_data->file->event_call));
1287
1288         if (data->count == -1)
1289                 seq_puts(m, ":unlimited");
1290         else
1291                 seq_printf(m, ":count=%ld", data->count);
1292
1293         if (data->filter_str)
1294                 seq_printf(m, " if %s\n", data->filter_str);
1295         else
1296                 seq_putc(m, '\n');
1297
1298         return 0;
1299 }
1300
1301 void event_enable_trigger_free(struct event_trigger_ops *ops,
1302                                struct event_trigger_data *data)
1303 {
1304         struct enable_trigger_data *enable_data = data->private_data;
1305
1306         if (WARN_ON_ONCE(data->ref <= 0))
1307                 return;
1308
1309         data->ref--;
1310         if (!data->ref) {
1311                 /* Remove the SOFT_MODE flag */
1312                 trace_event_enable_disable(enable_data->file, 0, 1);
1313                 module_put(enable_data->file->event_call->mod);
1314                 trigger_data_free(data);
1315                 kfree(enable_data);
1316         }
1317 }
1318
1319 static struct event_trigger_ops event_enable_trigger_ops = {
1320         .func                   = event_enable_trigger,
1321         .print                  = event_enable_trigger_print,
1322         .init                   = event_trigger_init,
1323         .free                   = event_enable_trigger_free,
1324 };
1325
1326 static struct event_trigger_ops event_enable_count_trigger_ops = {
1327         .func                   = event_enable_count_trigger,
1328         .print                  = event_enable_trigger_print,
1329         .init                   = event_trigger_init,
1330         .free                   = event_enable_trigger_free,
1331 };
1332
1333 static struct event_trigger_ops event_disable_trigger_ops = {
1334         .func                   = event_enable_trigger,
1335         .print                  = event_enable_trigger_print,
1336         .init                   = event_trigger_init,
1337         .free                   = event_enable_trigger_free,
1338 };
1339
1340 static struct event_trigger_ops event_disable_count_trigger_ops = {
1341         .func                   = event_enable_count_trigger,
1342         .print                  = event_enable_trigger_print,
1343         .init                   = event_trigger_init,
1344         .free                   = event_enable_trigger_free,
1345 };
1346
1347 int event_enable_trigger_func(struct event_command *cmd_ops,
1348                               struct trace_event_file *file,
1349                               char *glob, char *cmd, char *param)
1350 {
1351         struct trace_event_file *event_enable_file;
1352         struct enable_trigger_data *enable_data;
1353         struct event_trigger_data *trigger_data;
1354         struct event_trigger_ops *trigger_ops;
1355         struct trace_array *tr = file->tr;
1356         const char *system;
1357         const char *event;
1358         bool hist = false;
1359         char *trigger;
1360         char *number;
1361         bool enable;
1362         int ret;
1363
1364         if (!param)
1365                 return -EINVAL;
1366
1367         /* separate the trigger from the filter (s:e:n [if filter]) */
1368         trigger = strsep(&param, " \t");
1369         if (!trigger)
1370                 return -EINVAL;
1371
1372         system = strsep(&trigger, ":");
1373         if (!trigger)
1374                 return -EINVAL;
1375
1376         event = strsep(&trigger, ":");
1377
1378         ret = -EINVAL;
1379         event_enable_file = find_event_file(tr, system, event);
1380         if (!event_enable_file)
1381                 goto out;
1382
1383 #ifdef CONFIG_HIST_TRIGGERS
1384         hist = ((strcmp(cmd, ENABLE_HIST_STR) == 0) ||
1385                 (strcmp(cmd, DISABLE_HIST_STR) == 0));
1386
1387         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1388                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1389 #else
1390         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1391 #endif
1392         trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
1393
1394         ret = -ENOMEM;
1395         trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
1396         if (!trigger_data)
1397                 goto out;
1398
1399         enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL);
1400         if (!enable_data) {
1401                 kfree(trigger_data);
1402                 goto out;
1403         }
1404
1405         trigger_data->count = -1;
1406         trigger_data->ops = trigger_ops;
1407         trigger_data->cmd_ops = cmd_ops;
1408         INIT_LIST_HEAD(&trigger_data->list);
1409         RCU_INIT_POINTER(trigger_data->filter, NULL);
1410
1411         enable_data->hist = hist;
1412         enable_data->enable = enable;
1413         enable_data->file = event_enable_file;
1414         trigger_data->private_data = enable_data;
1415
1416         if (glob[0] == '!') {
1417                 cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
1418                 kfree(trigger_data);
1419                 kfree(enable_data);
1420                 ret = 0;
1421                 goto out;
1422         }
1423
1424         /* Up the trigger_data count to make sure nothing frees it on failure */
1425         event_trigger_init(trigger_ops, trigger_data);
1426
1427         if (trigger) {
1428                 number = strsep(&trigger, ":");
1429
1430                 ret = -EINVAL;
1431                 if (!strlen(number))
1432                         goto out_free;
1433
1434                 /*
1435                  * We use the callback data field (which is a pointer)
1436                  * as our counter.
1437                  */
1438                 ret = kstrtoul(number, 0, &trigger_data->count);
1439                 if (ret)
1440                         goto out_free;
1441         }
1442
1443         if (!param) /* if param is non-empty, it's supposed to be a filter */
1444                 goto out_reg;
1445
1446         if (!cmd_ops->set_filter)
1447                 goto out_reg;
1448
1449         ret = cmd_ops->set_filter(param, trigger_data, file);
1450         if (ret < 0)
1451                 goto out_free;
1452
1453  out_reg:
1454         /* Don't let event modules unload while probe registered */
1455         ret = try_module_get(event_enable_file->event_call->mod);
1456         if (!ret) {
1457                 ret = -EBUSY;
1458                 goto out_free;
1459         }
1460
1461         ret = trace_event_enable_disable(event_enable_file, 1, 1);
1462         if (ret < 0)
1463                 goto out_put;
1464         ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
1465         /*
1466          * The above returns on success the # of functions enabled,
1467          * but if it didn't find any functions it returns zero.
1468          * Consider no functions a failure too.
1469          */
1470         if (!ret) {
1471                 ret = -ENOENT;
1472                 goto out_disable;
1473         } else if (ret < 0)
1474                 goto out_disable;
1475         /* Just return zero, not the number of enabled functions */
1476         ret = 0;
1477         event_trigger_free(trigger_ops, trigger_data);
1478  out:
1479         return ret;
1480
1481  out_disable:
1482         trace_event_enable_disable(event_enable_file, 0, 1);
1483  out_put:
1484         module_put(event_enable_file->event_call->mod);
1485  out_free:
1486         if (cmd_ops->set_filter)
1487                 cmd_ops->set_filter(NULL, trigger_data, NULL);
1488         event_trigger_free(trigger_ops, trigger_data);
1489         kfree(enable_data);
1490         goto out;
1491 }
1492
1493 int event_enable_register_trigger(char *glob,
1494                                   struct event_trigger_ops *ops,
1495                                   struct event_trigger_data *data,
1496                                   struct trace_event_file *file)
1497 {
1498         struct enable_trigger_data *enable_data = data->private_data;
1499         struct enable_trigger_data *test_enable_data;
1500         struct event_trigger_data *test;
1501         int ret = 0;
1502
1503         lockdep_assert_held(&event_mutex);
1504
1505         list_for_each_entry(test, &file->triggers, list) {
1506                 test_enable_data = test->private_data;
1507                 if (test_enable_data &&
1508                     (test->cmd_ops->trigger_type ==
1509                      data->cmd_ops->trigger_type) &&
1510                     (test_enable_data->file == enable_data->file)) {
1511                         ret = -EEXIST;
1512                         goto out;
1513                 }
1514         }
1515
1516         if (data->ops->init) {
1517                 ret = data->ops->init(data->ops, data);
1518                 if (ret < 0)
1519                         goto out;
1520         }
1521
1522         list_add_rcu(&data->list, &file->triggers);
1523         ret++;
1524
1525         update_cond_flag(file);
1526         if (trace_event_trigger_enable_disable(file, 1) < 0) {
1527                 list_del_rcu(&data->list);
1528                 update_cond_flag(file);
1529                 ret--;
1530         }
1531 out:
1532         return ret;
1533 }
1534
1535 void event_enable_unregister_trigger(char *glob,
1536                                      struct event_trigger_ops *ops,
1537                                      struct event_trigger_data *test,
1538                                      struct trace_event_file *file)
1539 {
1540         struct enable_trigger_data *test_enable_data = test->private_data;
1541         struct enable_trigger_data *enable_data;
1542         struct event_trigger_data *data;
1543         bool unregistered = false;
1544
1545         lockdep_assert_held(&event_mutex);
1546
1547         list_for_each_entry(data, &file->triggers, list) {
1548                 enable_data = data->private_data;
1549                 if (enable_data &&
1550                     (data->cmd_ops->trigger_type ==
1551                      test->cmd_ops->trigger_type) &&
1552                     (enable_data->file == test_enable_data->file)) {
1553                         unregistered = true;
1554                         list_del_rcu(&data->list);
1555                         trace_event_trigger_enable_disable(file, 0);
1556                         update_cond_flag(file);
1557                         break;
1558                 }
1559         }
1560
1561         if (unregistered && data->ops->free)
1562                 data->ops->free(data->ops, data);
1563 }
1564
1565 static struct event_trigger_ops *
1566 event_enable_get_trigger_ops(char *cmd, char *param)
1567 {
1568         struct event_trigger_ops *ops;
1569         bool enable;
1570
1571 #ifdef CONFIG_HIST_TRIGGERS
1572         enable = ((strcmp(cmd, ENABLE_EVENT_STR) == 0) ||
1573                   (strcmp(cmd, ENABLE_HIST_STR) == 0));
1574 #else
1575         enable = strcmp(cmd, ENABLE_EVENT_STR) == 0;
1576 #endif
1577         if (enable)
1578                 ops = param ? &event_enable_count_trigger_ops :
1579                         &event_enable_trigger_ops;
1580         else
1581                 ops = param ? &event_disable_count_trigger_ops :
1582                         &event_disable_trigger_ops;
1583
1584         return ops;
1585 }
1586
1587 static struct event_command trigger_enable_cmd = {
1588         .name                   = ENABLE_EVENT_STR,
1589         .trigger_type           = ETT_EVENT_ENABLE,
1590         .func                   = event_enable_trigger_func,
1591         .reg                    = event_enable_register_trigger,
1592         .unreg                  = event_enable_unregister_trigger,
1593         .get_trigger_ops        = event_enable_get_trigger_ops,
1594         .set_filter             = set_trigger_filter,
1595 };
1596
1597 static struct event_command trigger_disable_cmd = {
1598         .name                   = DISABLE_EVENT_STR,
1599         .trigger_type           = ETT_EVENT_ENABLE,
1600         .func                   = event_enable_trigger_func,
1601         .reg                    = event_enable_register_trigger,
1602         .unreg                  = event_enable_unregister_trigger,
1603         .get_trigger_ops        = event_enable_get_trigger_ops,
1604         .set_filter             = set_trigger_filter,
1605 };
1606
1607 static __init void unregister_trigger_enable_disable_cmds(void)
1608 {
1609         unregister_event_command(&trigger_enable_cmd);
1610         unregister_event_command(&trigger_disable_cmd);
1611 }
1612
1613 static __init int register_trigger_enable_disable_cmds(void)
1614 {
1615         int ret;
1616
1617         ret = register_event_command(&trigger_enable_cmd);
1618         if (WARN_ON(ret < 0))
1619                 return ret;
1620         ret = register_event_command(&trigger_disable_cmd);
1621         if (WARN_ON(ret < 0))
1622                 unregister_trigger_enable_disable_cmds();
1623
1624         return ret;
1625 }
1626
1627 static __init int register_trigger_traceon_traceoff_cmds(void)
1628 {
1629         int ret;
1630
1631         ret = register_event_command(&trigger_traceon_cmd);
1632         if (WARN_ON(ret < 0))
1633                 return ret;
1634         ret = register_event_command(&trigger_traceoff_cmd);
1635         if (WARN_ON(ret < 0))
1636                 unregister_trigger_traceon_traceoff_cmds();
1637
1638         return ret;
1639 }
1640
1641 __init int register_trigger_cmds(void)
1642 {
1643         register_trigger_traceon_traceoff_cmds();
1644         register_trigger_snapshot_cmd();
1645         register_trigger_stacktrace_cmd();
1646         register_trigger_enable_disable_cmds();
1647         register_trigger_hist_enable_disable_cmds();
1648         register_trigger_hist_cmd();
1649
1650         return 0;
1651 }